diff --git a/config_host.mk.in b/config_host.mk.in
index 15b82b07ffb2..d759bc2d9ce5 100644
--- a/config_host.mk.in
+++ b/config_host.mk.in
@@ -176,6 +176,7 @@ ENABLE_DOTNET=@ENABLE_DOTNET@
 SYSTEM_DRAGONBOX=@SYSTEM_DRAGONBOX@
 SYSTEM_FROZEN=@SYSTEM_FROZEN@
 export ENABLE_EMSCRIPTEN_PROXY_POSIX_SOCKETS=@ENABLE_EMSCRIPTEN_PROXY_POSIX_SOCKETS@
+export ENABLE_EMSCRIPTEN_PROXY_TO_PTHREAD=@ENABLE_EMSCRIPTEN_PROXY_TO_PTHREAD@
 export ENABLE_EPOXY=@ENABLE_EPOXY@
 export ENABLE_EOT=@ENABLE_EOT@
 export ENABLE_EVOAB2=@ENABLE_EVOAB2@
diff --git a/config_host/config_emscripten.h.in b/config_host/config_emscripten.h.in
index 24d1a9ca5dd8..d8121613a934 100644
--- a/config_host/config_emscripten.h.in
+++ b/config_host/config_emscripten.h.in
@@ -11,4 +11,6 @@
 
 #define HAVE_EMSCRIPTEN_PROXY_POSIX_SOCKETS 0
 
+#define HAVE_EMSCRIPTEN_PROXY_TO_PTHREAD 0
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/configure.ac b/configure.ac
index 026e81caeb85..dd2954a283b8 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2167,6 +2167,15 @@ AC_ARG_WITH(main-module,
         Default value is 'writer'.]),
 ,)
 
+if test "$_os" = Emscripten; then
+    AC_ARG_ENABLE(emscripten-proxy-to-pthread,
+        AS_HELP_STRING([--disable-emscripten-proxy-to-pthread],
+            [Experimentally disable use of the Emscripten -sPROXY_TO_PTHREAD feature.]),,
+        enable_emscripten_proxy_to_pthread=yes)
+else
+    enable_emscripten_proxy_to_pthread=
+fi
+
 if test "$_os" = Emscripten; then
     AC_ARG_ENABLE(emscripten-proxy-posix-sockets,
         AS_HELP_STRING([--enable-emscripten-proxy-posix-sockets],
@@ -4177,6 +4186,14 @@ AC_SUBST(ENABLE_WASM_STRIP)
 AC_SUBST(ENABLE_WASM_STRIP_WRITER)
 AC_SUBST(ENABLE_WASM_STRIP_CALC)
 
+if test "$enable_emscripten_proxy_to_pthread" = yes; then
+    ENABLE_EMSCRIPTEN_PROXY_TO_PTHREAD=TRUE
+    AC_DEFINE(HAVE_EMSCRIPTEN_PROXY_TO_PTHREAD)
+else
+    ENABLE_EMSCRIPTEN_PROXY_TO_PTHREAD=
+fi
+AC_SUBST(ENABLE_EMSCRIPTEN_PROXY_TO_PTHREAD)
+
 if test "$enable_emscripten_proxy_posix_sockets" = yes; then
     ENABLE_EMSCRIPTEN_PROXY_POSIX_SOCKETS=TRUE
     AC_DEFINE(HAVE_EMSCRIPTEN_PROXY_POSIX_SOCKETS)
diff --git a/desktop/Executable_soffice_bin.mk b/desktop/Executable_soffice_bin.mk
index fcf16e041fb9..a791e8f362e4 100644
--- a/desktop/Executable_soffice_bin.mk
+++ b/desktop/Executable_soffice_bin.mk
@@ -63,8 +63,10 @@ $(call gb_Executable_get_linktarget_target,soffice_bin): \
 
 $(eval $(call gb_Executable_add_ldflags,soffice_bin,\
 	-s EXPORTED_FUNCTIONS=@$(gb_CustomTarget_workdir)/desktop/soffice_bin-emscripten-exports/exports -Wl$(COMMA)--whole-archive $(call gb_StaticLibrary_get_target,unoembind) -Wl$(COMMA)--no-whole-archive \
-	-sPROXY_TO_PTHREAD=1 \
-	$(if $(DISABLE_GUI),,-sOFFSCREENCANVAS_SUPPORT=1 -sOFFSCREENCANVASES_TO_PTHREAD=\#qtcanvas) \
+	$(if $(ENABLE_EMSCRIPTEN_PROXY_TO_PTHREAD), \
+	    -sPROXY_TO_PTHREAD=1 \
+	    $(if $(DISABLE_GUI),, \
+	        -sOFFSCREENCANVAS_SUPPORT=1 -sOFFSCREENCANVASES_TO_PTHREAD=\#qtcanvas)) \
 ))
 ifeq ($(ENABLE_QT6),TRUE)
 $(eval $(call gb_Executable_add_ldflags,soffice_bin, \
diff --git a/desktop/source/app/appinit.cxx b/desktop/source/app/appinit.cxx
index 16f023b0a414..6c7637f32f9e 100644
--- a/desktop/source/app/appinit.cxx
+++ b/desktop/source/app/appinit.cxx
@@ -54,6 +54,7 @@
 #include <emscripten/threading.h>
 #include <emscripten/val.h>
 #include <bindings_uno.hxx>
+#include <config_emscripten.h>
 #endif
 
 using namespace ::com::sun::star::uno;
@@ -94,12 +95,20 @@ EM_JS(void, setupMainChannel, (), {
 });
 
 extern "C" void resolveUnoMain(pthread_t id) {
+#if HAVE_EMSCRIPTEN_PROXY_TO_PTHREAD
     EM_ASM({
         const sofficeMain = PThread.pthreads[$0];
         const channel = new MessageChannel();
         sofficeMain.postMessage({cmd:"LOWA-channel"}, [channel.port2]);
         Module.uno_main$resolve(channel.port1);
     }, id);
+#else
+    EM_ASM({
+        const channel = new MessageChannel();
+        postMessage({cmd:"LOWA-channel"}, [channel.port2]);
+        Module.uno_main$resolve(channel.port1);
+    }, id);
+#endif
 }
 
 void initUno() {
diff --git a/solenv/gbuild/platform/EMSCRIPTEN_INTEL_GCC.mk b/solenv/gbuild/platform/EMSCRIPTEN_INTEL_GCC.mk
index 2b55b4ba1218..4951bb1cae03 100644
--- a/solenv/gbuild/platform/EMSCRIPTEN_INTEL_GCC.mk
+++ b/solenv/gbuild/platform/EMSCRIPTEN_INTEL_GCC.mk
@@ -17,6 +17,10 @@ gb_EMSCRIPTEN_LDFLAGS := $(gb_EMSCRIPTEN_CPPFLAGS)
 # Initial memory size
 gb_EMSCRIPTEN_LDFLAGS += -s TOTAL_MEMORY=1GB
 
+ifeq ($(ENABLE_EMSCRIPTEN_PROXY_TO_PTHREAD),)
+gb_EMSCRIPTEN_LDFLAGS += -sPTHREAD_POOL_SIZE=6
+endif
+
 # Double the main thread stack size, but keep the default value for other threads:
 gb_EMSCRIPTEN_LDFLAGS += -sSTACK_SIZE=131072 -sDEFAULT_PTHREAD_STACK_SIZE=65536